//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include <__assert>
#include <cerrno>
#include <charconv>
#include <cstdlib>
#include <limits>
#include <stdexcept>
#include <stdio.h>
#include <string>

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
#  include <cwchar>
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

#ifndef _LIBCPP_ABI_DO_NOT_EXPORT_BASIC_STRING_COMMON

template <bool>
struct __basic_string_common;

// The struct isn't declared anymore in the headers. It's only here for ABI compatibility.
template <>
struct __basic_string_common<true> {
    _LIBCPP_NORETURN _LIBCPP_EXPORTED_FROM_ABI void __throw_length_error() const;
    _LIBCPP_NORETURN _LIBCPP_EXPORTED_FROM_ABI void __throw_out_of_range() const;
};

void __basic_string_common<true>::__throw_length_error() const {
    std::__throw_length_error("basic_string");
}
void __basic_string_common<true>::__throw_out_of_range() const {
    std::__throw_out_of_range("basic_string");
}

#endif // _LIBCPP_ABI_DO_NOT_EXPORT_BASIC_STRING_COMMON

#define _LIBCPP_EXTERN_TEMPLATE_DEFINE(...) template __VA_ARGS__;
#ifdef _LIBCPP_ABI_STRING_OPTIMIZED_EXTERNAL_INSTANTIATION
    _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE_DEFINE, char)
#   ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
        _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE_DEFINE, wchar_t)
#   endif
#else
    _LIBCPP_STRING_V1_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE_DEFINE, char)
#   ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
        _LIBCPP_STRING_V1_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE_DEFINE, wchar_t)
#   endif
#endif
#undef _LIBCPP_EXTERN_TEMPLATE_DEFINE

template string operator+<char, char_traits<char>, allocator<char> >(char const*, string const&);

namespace
{

template<typename T>
inline
void throw_helper( const string& msg )
{
#ifndef _LIBCPP_NO_EXCEPTIONS
    throw T( msg );
#else
    fprintf(stderr, "%s\n", msg.c_str());
    _VSTD::abort();
#endif
}

inline
void throw_from_string_out_of_range( const string& func )
{
    throw_helper<out_of_range>(func + ": out of range");
}

inline
void throw_from_string_invalid_arg( const string& func )
{
    throw_helper<invalid_argument>(func + ": no conversion");
}

// as_integer

template<typename V, typename S, typename F>
inline
V
as_integer_helper(const string& func, const S& str, size_t* idx, int base, F f)
{
    typename S::value_type* ptr = nullptr;
    const typename S::value_type* const p = str.c_str();
    typename remove_reference<decltype(errno)>::type errno_save = errno;
    errno = 0;
    V r = f(p, &ptr, base);
    swap(errno, errno_save);
    if (errno_save == ERANGE)
        throw_from_string_out_of_range(func);
    if (ptr == p)
        throw_from_string_invalid_arg(func);
    if (idx)
        *idx = static_cast<size_t>(ptr - p);
    return r;
}

template<typename V, typename S>
inline
V
as_integer(const string& func, const S& s, size_t* idx, int base);

// string
template<>
inline
int
as_integer(const string& func, const string& s, size_t* idx, int base )
{
    // Use long as no Standard string to integer exists.
    long r = as_integer_helper<long>( func, s, idx, base, strtol );
    if (r < numeric_limits<int>::min() || numeric_limits<int>::max() < r)
        throw_from_string_out_of_range(func);
    return static_cast<int>(r);
}

template<>
inline
long
as_integer(const string& func, const string& s, size_t* idx, int base )
{
    return as_integer_helper<long>( func, s, idx, base, strtol );
}

template<>
inline
unsigned long
as_integer( const string& func, const string& s, size_t* idx, int base )
{
    return as_integer_helper<unsigned long>( func, s, idx, base, strtoul );
}

template<>
inline
long long
as_integer( const string& func, const string& s, size_t* idx, int base )
{
    return as_integer_helper<long long>( func, s, idx, base, strtoll );
}

template<>
inline
unsigned long long
as_integer( const string& func, const string& s, size_t* idx, int base )
{
    return as_integer_helper<unsigned long long>( func, s, idx, base, strtoull );
}

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
// wstring
template<>
inline
int
as_integer( const string& func, const wstring& s, size_t* idx, int base )
{
    // Use long as no Stantard string to integer exists.
    long r = as_integer_helper<long>( func, s, idx, base, wcstol );
    if (r < numeric_limits<int>::min() || numeric_limits<int>::max() < r)
        throw_from_string_out_of_range(func);
    return static_cast<int>(r);
}

template<>
inline
long
as_integer( const string& func, const wstring& s, size_t* idx, int base )
{
    return as_integer_helper<long>( func, s, idx, base, wcstol );
}

template<>
inline
unsigned long
as_integer( const string& func, const wstring& s, size_t* idx, int base )
{
    return as_integer_helper<unsigned long>( func, s, idx, base, wcstoul );
}

template<>
inline
long long
as_integer( const string& func, const wstring& s, size_t* idx, int base )
{
    return as_integer_helper<long long>( func, s, idx, base, wcstoll );
}

template<>
inline
unsigned long long
as_integer( const string& func, const wstring& s, size_t* idx, int base )
{
    return as_integer_helper<unsigned long long>( func, s, idx, base, wcstoull );
}
#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS

// as_float

template<typename V, typename S, typename F>
inline
V
as_float_helper(const string& func, const S& str, size_t* idx, F f )
{
    typename S::value_type* ptr = nullptr;
    const typename S::value_type* const p = str.c_str();
    typename remove_reference<decltype(errno)>::type errno_save = errno;
    errno = 0;
    V r = f(p, &ptr);
    swap(errno, errno_save);
    if (errno_save == ERANGE)
        throw_from_string_out_of_range(func);
    if (ptr == p)
        throw_from_string_invalid_arg(func);
    if (idx)
        *idx = static_cast<size_t>(ptr - p);
    return r;
}

template<typename V, typename S>
inline
V as_float( const string& func, const S& s, size_t* idx = nullptr );

template<>
inline
float
as_float( const string& func, const string& s, size_t* idx )
{
    return as_float_helper<float>( func, s, idx, strtof );
}

template<>
inline
double
as_float(const string& func, const string& s, size_t* idx )
{
    return as_float_helper<double>( func, s, idx, strtod );
}

template<>
inline
long double
as_float( const string& func, const string& s, size_t* idx )
{
    return as_float_helper<long double>( func, s, idx, strtold );
}

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
template<>
inline
float
as_float( const string& func, const wstring& s, size_t* idx )
{
    return as_float_helper<float>( func, s, idx, wcstof );
}

template<>
inline
double
as_float( const string& func, const wstring& s, size_t* idx )
{
    return as_float_helper<double>( func, s, idx, wcstod );
}

template<>
inline
long double
as_float( const string& func, const wstring& s, size_t* idx )
{
    return as_float_helper<long double>( func, s, idx, wcstold );
}
#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS

}  // unnamed namespace

int
stoi(const string& str, size_t* idx, int base)
{
    return as_integer<int>( "stoi", str, idx, base );
}

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
int
stoi(const wstring& str, size_t* idx, int base)
{
    return as_integer<int>( "stoi", str, idx, base );
}
#endif

long
stol(const string& str, size_t* idx, int base)
{
    return as_integer<long>( "stol", str, idx, base );
}

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
long
stol(const wstring& str, size_t* idx, int base)
{
    return as_integer<long>( "stol", str, idx, base );
}
#endif

unsigned long
stoul(const string& str, size_t* idx, int base)
{
    return as_integer<unsigned long>( "stoul", str, idx, base );
}

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
unsigned long
stoul(const wstring& str, size_t* idx, int base)
{
    return as_integer<unsigned long>( "stoul", str, idx, base );
}
#endif

long long
stoll(const string& str, size_t* idx, int base)
{
    return as_integer<long long>( "stoll", str, idx, base );
}

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
long long
stoll(const wstring& str, size_t* idx, int base)
{
    return as_integer<long long>( "stoll", str, idx, base );
}
#endif

unsigned long long
stoull(const string& str, size_t* idx, int base)
{
    return as_integer<unsigned long long>( "stoull", str, idx, base );
}

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
unsigned long long
stoull(const wstring& str, size_t* idx, int base)
{
    return as_integer<unsigned long long>( "stoull", str, idx, base );
}
#endif

float
stof(const string& str, size_t* idx)
{
    return as_float<float>( "stof", str, idx );
}

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
float
stof(const wstring& str, size_t* idx)
{
    return as_float<float>( "stof", str, idx );
}
#endif

double
stod(const string& str, size_t* idx)
{
    return as_float<double>( "stod", str, idx );
}

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
double
stod(const wstring& str, size_t* idx)
{
    return as_float<double>( "stod", str, idx );
}
#endif

long double
stold(const string& str, size_t* idx)
{
    return as_float<long double>( "stold", str, idx );
}

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
long double
stold(const wstring& str, size_t* idx)
{
    return as_float<long double>( "stold", str, idx );
}
#endif

// to_string

namespace
{

// as_string

template<typename S, typename P, typename V >
inline
S
as_string(P sprintf_like, S s, const typename S::value_type* fmt, V a)
{
    typedef typename S::size_type size_type;
    size_type available = s.size();
    while (true)
    {
        int status = sprintf_like(&s[0], available + 1, fmt, a);
        if ( status >= 0 )
        {
            size_type used = static_cast<size_type>(status);
            if ( used <= available )
            {
                s.resize( used );
                break;
            }
            available = used; // Assume this is advice of how much space we need.
        }
        else
            available = available * 2 + 1;
        s.resize(available);
    }
    return s;
}

template <class S>
struct initial_string;

template <>
struct initial_string<string>
{
    string
    operator()() const
    {
        string s;
        s.resize(s.capacity());
        return s;
    }
};

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
template <>
struct initial_string<wstring>
{
    wstring
    operator()() const
    {
        wstring s(20, wchar_t());
        s.resize(s.capacity());
        return s;
    }
};

typedef int (*wide_printf)(wchar_t* __restrict, size_t, const wchar_t*__restrict, ...);

inline
wide_printf
get_swprintf()
{
#ifndef _LIBCPP_MSVCRT
    return swprintf;
#else
    return static_cast<int (__cdecl*)(wchar_t* __restrict, size_t, const wchar_t*__restrict, ...)>(_snwprintf);
#endif
}
#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS

template <typename S, typename V>
S i_to_string(V v)
{
//  numeric_limits::digits10 returns value less on 1 than desired for unsigned numbers.
//  For example, for 1-byte unsigned value digits10 is 2 (999 can not be represented),
//  so we need +1 here.
    constexpr size_t bufsize = numeric_limits<V>::digits10 + 2;  // +1 for minus, +1 for digits10
    char buf[bufsize];
    const auto res = to_chars(buf, buf + bufsize, v);
    _LIBCPP_ASSERT(res.ec == errc(), "bufsize must be large enough to accomodate the value");
    return S(buf, res.ptr);
}

}  // unnamed namespace

string  to_string (int val)                { return i_to_string< string>(val); }
string  to_string (long val)               { return i_to_string< string>(val); }
string  to_string (long long val)          { return i_to_string< string>(val); }
string  to_string (unsigned val)           { return i_to_string< string>(val); }
string  to_string (unsigned long val)      { return i_to_string< string>(val); }
string  to_string (unsigned long long val) { return i_to_string< string>(val); }

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
wstring to_wstring(int val)                { return i_to_string<wstring>(val); }
wstring to_wstring(long val)               { return i_to_string<wstring>(val); }
wstring to_wstring(long long val)          { return i_to_string<wstring>(val); }
wstring to_wstring(unsigned val)           { return i_to_string<wstring>(val); }
wstring to_wstring(unsigned long val)      { return i_to_string<wstring>(val); }
wstring to_wstring(unsigned long long val) { return i_to_string<wstring>(val); }
#endif

string  to_string (float val)       { return as_string(snprintf,       initial_string< string>()(),   "%f", val); }
string  to_string (double val)      { return as_string(snprintf,       initial_string< string>()(),   "%f", val); }
string  to_string (long double val) { return as_string(snprintf,       initial_string< string>()(),  "%Lf", val); }

#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
wstring to_wstring(float val)       { return as_string(get_swprintf(), initial_string<wstring>()(),  L"%f", val); }
wstring to_wstring(double val)      { return as_string(get_swprintf(), initial_string<wstring>()(),  L"%f", val); }
wstring to_wstring(long double val) { return as_string(get_swprintf(), initial_string<wstring>()(), L"%Lf", val); }
#endif

_LIBCPP_END_NAMESPACE_STD
